A staff member at Georgetown Preparatory School was arrested Wednesday after admitting to bringing a gun onto school property and keeping it on his desk, according to police charging documents obtained by News4. Pat Collins reports. (Published Thursday, Nov. 7, 2013)

A staff member at Georgetown Preparatory School was arrested Wednesday after admitting to bringing a gun onto school property and keeping it on his desk, according to police charging documents obtained exclusively by News4.

Stephen P. Lafferty, 46, of Frederick, Md., was charged with having a deadly weapon on school property and possession of drug paraphernalia Wednesday afternoon.

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Lafferty was arrested after other employees called Montgomery County Police to the all-boys' private Jesuit high school in Bethesda, Md. The employees told authorities that another coworker had sent a picture to the Dean of Students, showing him there was a gun in Lafferty's office.

According to charging documents obtained by News4, officers had Lafferty exit the building and asked them if he had any weapons on him. Lafferty told them no, but when asked if he had any weapons inside his office, he admitted there was, according to charging documents.

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Officers found a Smith and Wesson Model 500 50-caliber weapon with a scope on it.

Lafferty told them he had brought the gun to school so a man could install the scope on his gun. The school is a midway point between their homes in Frederick and Prince William County.

The gun wasn't loaded and was inside a holster on the desk, according to police.

An email from Jeffrey L. Jones, acting president and headmaster of Georgetown Prep, told the school community that no threats were made, and that Georgetown Prep followed the school's emergency protocol.

"The Montgomery County Police contained the situation without incident and the staff member and the weapon were removed from campus," Jones said in the email.

Jones' email does not mention Lafferty by name, but later says, "Given the recent improvements in security, procedures, and communication, I can tell you with every confidence that a difficult situation was handled without disturbing the work of the school."

During a search, police also found a socket with a wire filter inside it, which smelled like burned marijuana, inside Lafferty's pocket, according to charging documents.

The documents do not define Lafferty's role at the school, and a profile of Lafferty on the Georgetown Prep website appears to have been removed. However, Google archives seem to indicate that a "Steve Lafferty" worked in the school's Buildings and Grounds department.